This section provides background information related to the present disclosure which is not necessarily prior art.
Many new low global warming potential (LGWP) refrigerants are currently being developed and incorporated into widespread applications, and many of these refrigerants are flammable. With the recent introduction of the new and flammable LGWP refrigerants used in heating, ventilation, air conditioning, and refrigeration (HVAC&R) systems, it is desired to have robust and cost effective sensors to detect refrigerant leaks in homes and businesses to assure public safety. Electronic leak detection systems are currently available to detect gases, including various refrigerant gases. Carbon monoxide detection in residential homes is an example.
Direct detection of a refrigerant gas, especially certain flammable refrigerant gases, can be unreliable. Certain flammable refrigerant gases are more difficult to predictably and accurately detect with sensors. Further, many conventional sensors may have detection limits that are undesirably high for a specific flammable refrigerant. If the detection limit is too high, there is a risk that the flammable refrigerant may leak from the sealed system and accumulate to a concentration above its lower flammability limit. Unfortunately, the sensitivity of most sensors varies depending upon the refrigerant type and is often not completely adequate. Moreover, sensor selectivity suffers from either being over-selective or under-selective, where “selectivity” as used herein refers to the ability of a sensor to detect a specific analyte of interest at low detection limits without being triggered by other innocuous compounds to indicate a false positive. For example, some sensors exhibit a false positive alarm in the presence of perfume or cologne. Conversely, some gases, in order to be adequately detected at appropriate detection limits, require a very specialized sensor, which adds technical complexity and cost that will hinder its use for the average consumer. Thus, the current and new LGWP flammable refrigerants are difficult to reliably and accurately detect at the detection limits required with the current sensing systems.
There remains a need to develop a sensor system for leak detection that is both highly sensitive with low detection limits, has adequate selectivity, is accurate in detecting the flammable refrigerant, robust and highly reliable, but which is also low cost. Furthermore, it would be desirable to have a universal leak detection system compatible with multiple different refrigerants. Such a system desirably has little dependence on the refrigerant type, so that multiple flammable LGWP refrigerant gases may be detected by a single leak detection system.